“Maybe I try too hard to one up Harding #pll100,” Keegan captioned a photo of himself and Ian together at the Pretty Little Liars 100th episode celebration. Ian is wearing a nice, subtle pair of sunglasses. Keegan has on a giant — like, dunce-sized —pair of bright orange sunglasses. Oh, man. We love these two (because both of their deadpan expressions totally make the joke).

Keegan wasn’t done teasing Ian with his Instagram captions. Later in the night, he shared a photo of himself with Ian and Lucy Hale (Aria), captioned: “The ever charming and extremely sweet @lucyhaleand some random dude named E-yan? #pll100.” Ha! We love that the celebration of the 100th episode of Pretty Little Liars not only marks a milestone in the creative achievement of the show itself, but also in four years of working together. This group of family has become a family, as evidenced by showrunner Marlene King’s photo of the group cutting the giant cake together.

“Happy 100th episode to my dearest and sweetest PLL family. I'm so blessed to be on this journey with you,” Marlene tweeted yesterday, along with a photo of the main cast helping her cut an “A”-mazing cake. Keegan also tweeted the photo, with his own caption: “100 episodes #pll100 I'm so lucky and blessed to be a part of this show. Thank you to the fans the Pll cast and crew.” Have we mentioned that we love this cast and crew?

Catch the Season 5 premiere of Pretty Little Liars on Tuesday, June 10 at 8 p.m. ET on ABC Family.

Kayti Burt is a contributing writer for Wetpaint Entertainment with a penchant for all things pop culture. Follow her on Twitter and Google+!